Abstract 23P
Background
Chimeric Antigen Receptor (CAR) T-cell therapy has been a clinical breakthrough in hematological malignancies; however, it is still facing multifactorial challenges for clinical success in solid tumor, such as the selection of a proper target to avoid on-target off-tumor toxicities. To this extent, we characterized the monoclonal antibody MBr1 that specifically recognizes Globo-H cell-surface glycan to develop novel CAR T cells. Globo-H is overexpressed on several epithelial solid cancers, including the treatment-orphan cholangiocarcinoma, while it is minimally expressed on normal tissues, making it an attractive tumor-associated antigen.
Methods
MBr1 specific single chain variable fragment (scFv) was cloned into second generation retroviral vectors to generate both anti-Globo-H.CAR.CD28 and anti-GloboH.CAR.41BB T cells. Then, they were ex-vivo expanded, phenotypically characterized and assessed preclinically for their anti-tumor responses.
Results
We demonstrated that anti-Globo-H.CAR T cells exert robust anti-tumor activity mediated by Globo-H specific induction in vitro and in vivo. Indeed, both anti-Globo-H.CAR.CD28 and anti-GloboH.CAR.41BB T cells specifically killed Globo-H-positive cancer cell lines, whereas Globo H-negative tumor cells were not targeted. Although we have not found differences in terms of anti-tumor activity between anti-GloboH.CAR.41BB and anti-Globo-H.CAR.CD28 T cells, they showed significantly distinct phenotypic traits. The first displayed higher frequency of early differentiated T cells (Central Memory, TCM and Stem cell memory, TSCM), while the latter was enriched in effector memory T cells (TEM), conferring higher persistency or rapid effector functions, respectively. Lastly, we infused anti-Globo-H.CAR T cells in EGI-1 (cholangiocarcinoma cell line) xenotransplanted NSG mice, resulting in a significant reduction of the tumor volume following their homing in the tumor bed.
Conclusions
Our data strongly validated the antigen-mediated cytotoxicity of anti-Globo-H.CAR T cells in vitro, and their anti-tumor efficacy in vivo. Experiments conducted under GMP procedures are ongoing to validate its therapeutic potential paving the way for its clinical translation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Regione Lombardia: FORCE4CURE project.
Disclosure
All authors have declared no conflicts of interest.